Sealing chimney cap

[tommos43]

Hope someone can help me here.

Chimney has been capped by my gas fitter.

Since I have had issues with damp and water coming in.

Checked the cap and it looks OK but I wrapped plastic over it and it has halted the leaks.

Is there any sealant you could recommend that I could paint over the cap to seal it?

[jcgrumbles]

what kind of cowling is it? Get him back out...you shouldn't have to use silicone on it at all

[neilsignum]

An unused chimney should never be sealed or you'll get condensation, it should have a vent in the pot (most common are usually a mushroom shape cap with vents under the overhang) and then the chimney needs a trickle vent near the base (on the outside to stop draughts) to allow airflow. If you cap the top completely then you'd need to have a vent as near to top as possible - again that can be from outside.

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[tommos43]

Thanks guys I agree but he is adamant this is how he always caps off a chimney when the boiler and fire have been decommissioned.

I have coated the top of the chimney with two coats of bitumen paint will see how that shapes up!

If this fails then a vent/cowl will be my next job.

[blueflash234]

i always used to cement the cowl on to the stack you should not need sealant